def resolve():
    x = int(input())
    if x >= 30:
        print('Yes')
        return
    print('No')
resolve() def resolve():
    x = int(input())
    if x >= 30:
        print('Yes')
        return
    print('No') resolve x = int(input()) x int(input()) int input() input if x >= 30:
        print('Yes')
        return
     x >= 30 x 30 print('Yes') print 'Yes' return print('No') print 'No' resolve() resolve def resolve():
    x = int(input())
    if x >= 30:
        print('Yes')
        return
    print('No') def resolve():
    x = int(input())
    if x >= 30:
        print('Yes')
        return
    print('No') resolve
def resolve():
    x = int(input())
    if x >= 30:
        print('Yes')
        return
    print('No')
resolve()